Electric alarm device



Aug. 31, 1948. -w. P. T. HOLM "7" ELECTRIC ALARM DEVICE Filed Nov. s,1945 ATTO RNEY ELEoTRIc ALARM Davids l Walter P. T. Holm, Buenos Aires,Argentina, as-

signor to Vibra Co. Soc. de Resp. Ltda., Buenos Aires, Argentina, a..corporation of Argentina.v

v'This invention relates to burglar and fire :alarm devices, and moreparticularly to vibration and heat sensitive switches. i y

One object of the invention is to provide means highly sensitive to'vibration and heat to close a circuit to an Ialarm device in the eventof any attempt at burglary or fire, which means when disposed whereverdesired Will be a safeguard against'such events.

vAnother object is to provide a device of this vtype with a pendulumsuspension highly sensitive to both vibrations and heat so as to preventthe same from working ineiilciently. "i-fThe most outstanding feature ofthe'apparatus resides in that it provides a pendulum mounted in such amanner as to act as the breaker of a circuit` enclosing directly orindirectly one or more alarm elements l(bells, lights, etc.). Thebreaking of the current takes place between the rod of the pendulumproper and one or more contact terminals located near the rod, thesecontact terminals being `made of a good conducting material -capable ofdeforming or expanding under th'e effect of heat. i ylin the case of atrespass or a theft taking place at the spot where the apparatus islocated, i. e.,

When this device suiers any vibration due to these causes, the pendulumwill take on an oscillation of such a magnitude as to cause its rod totouch the said terminal or terminals, thereby closing lthe electriccircuit and producing the desired alarm.

. fn the lcase of a fire, the terminal or terminals will become deformedor will expand so that the pendulum,l even if it stands still, will betouched bythe said terminal or terminals to produce the closing of theelectric circuit and, consequently, the said alarm, in the same manneras hereinbefore stated.

It is evident that the electric circuit may cornprise an electromagnet,a relay, a motor, etc., to keep this circuit closed once it is closed orkeep closed any other circuit comprising the alarm contrivances so as tohave the alarm go on until it is interrupted by its correspondingswitch.

Inorder that the invention may be readily understood and put intopractice it is shown by way of example in the attached drawing by meansof various illustrative figures wherein:

Figure 1 is a front view of the device according to the invention, withits lid removed, and showing the support of the penduluml in sectionalview.

Figure 2 is a sectional view along the line A-A of the foregoing ligure,with the lid on,

'Application November 5, 1945, Serial No. 626,628 l l In Argentina Aprilv30, 1945 i '.1

comme. (ci. zoo- 138i f a l' igure 3 is a-sectional View of Figure 1,

VFigure 4 is a Vfront elevational View on a re-f duced scale of thedevice, and y I i Figure 5 is the electric Wiring' diagram of the alongthe line -C--C apparatus. I

In the different figures of the drawing similar parts are indicated bythe same reference numerals.

The construction in accordance with the model shown consists of anelectrically insulating base I on which is mounted by means of 'screws 2a support 3 made of a good conducting material. To provide foradjustment of support 3 these screws pass through lengthened holes 4 inthe said support 3, as will be appreciated from Figs.

1 and 3. l i

-On this bracket-like support 3 rests a pendulum rod 5 which passesthrough a slot 6 in the bracket and ends in an inverted cradle 'l havingpointed ends. As is seen from Fig. 1, the cradle 1 rests in `two conicalcavities 8 in support 3 -so as to cause the same to offer the leastpossible resistance when the pendulum oscillates. All these elements, i.e., support 3, rod 5 of the pendulum and cradle I are made of a goodconducting material or materials.

In order to prevent the rod 5 from being accidentally dislodged from thesupport it is provided with a suitable means such as the ring 9 having apressure-screw Iii and located near the bottom portion of the horizontalWing of support 3. In this manner, the cradle 'l of the pendulum cannotescape unless the pressure-screw I0 is loosened and the ring 9 moveddown until the tips of the cradle can `clear the conical cavities 8, aswill be readily understood.

The support 3 may be equipped with any suitable means for controllingits position (low or high). ing, is a simple eccentric I I engaging anotch of the support and mounted on the `base I. It may be turned bymeans of a key or an instrument like the rod I2 one end of which issquare shaped in cross section and engages the eccentric body Il whilethe other end carries a knob I2 to ODerate it (Figs. 2 and 4). I

The rod 5 suspended in th'e manner as has been described hereinbeforeextends downwardly and receives at its lower end the weight I3 thusconstituting the pendulum of the device. This rod 5 has intermediate theends thereof a small bolt I4 extending therethrough and rigidly aiiixedthereto. I 1 f il Near the bolt I4, at a different level, for ex- Thismeans, in the example of the draw a support I6 which is mounted on thebase I by A means .of screws I1 that pass through a slot I8 of thesupport to permit adjustment of its height.-

The electric connection of vthe device is, as in the case of ordinarycircuit-breakers, ef-

fected in series with the elements and contrivances producing thecorresponding alarm, the

cables I9 and 20 being connected to the screws.:

2 and I1, respectively (Fig. l). A lid 2| covering the device as aprotecting means (Figs. 2 and 4) has the necessary orifices or openingsfor the said cables I9 and 20 to pass therethrough (provided they do notpass through the base I), as well as the openings 22 (Fig. 4) for theinsertion of a screw driver to operate the screws 2 whenever it isdesired to adjust the position of the support 3 by means of the knob I2and the eccentric II, and opening 23 (Fig. 2) to allow heat to pass incase of a fire. The device operates as follows:

With the apparatus put in the pl-ace where it is needed, for example, adoor, a display-window, a vehicle, etc., and the electric currentconnected thereto, any movement of such-door, window, etc., will inducea vibration which, in turn, will cause the pendulum to oscillateimmediately. When the pendulum swings, rod will make contact with one ofthe wires I5 or with both, thereby closing the electric circuit whichwill start the alarm installation. Again, when there is a fire, the heatreceived by the wire -or the wires I5 will cause the same to form anarch or bend towards and make contact with the through-bolt I4 of therod 5, whereby the circuit is closed as in the foregoing ease, even ifthe pendulum remains motionless. To increase the heat sensitivity of thedevice, the rod 5, or a portion thereof, may be made of a materialhaving a high coeiicient of expansion, so that the bolt I4 may touch thewires I5 for the desired purpose. n In certain cases, the bolt I4 may bedispensed with, if the direction in which the wires I5 are bent istowards the rod 5, the electric circuit being closed in the same mannerin the event of are. l

To sensitize the apparatus or to condition to the temperature ranges ofsummer and winter, all that is necessary is to raise or lower theposition of support 3 by the aid of its adjusting means, viz, theeccentric II', rod I2, knob I2 andscrews2. l

Also, the wires I5 may be spaced from rod 5 and its bolt I4, as may bedeemed necessary. I

.What is claimed is: l y i vl, l. A heat and vibration sensitive switch,comprising a nonconducting base, a pendulum support connected to saidbase, a pendulum rod carried by said support, a second support connectedto said base, at least one thermoscopic rod connected to said secondsupport and adjacent said pendulum rod, and a bolt carried by. saidpendulum rod extending transversely through the same and adjacent saidthermoscopic rod.

' jlf" 2,448,181

l 3. .A heat Iand vibration sensitive switch, compri'sing ianon-conducting base, a pendulum support connected to said base, saidsupport having a slot formed therein and two conical cavities spacedfrom said slot, a pendulum rod extending through said slot, an invertedcradle l, memberat one' end of said pendulum rod adapted to seat in saidconical cavities, a second support connected to said base, at least onethermoscopic rod connected to said second support and adjacent saidpendulum rod, and a bolt carried by said l pendulum rod extending4transversely through the same and adjacent said thermoscopic rod.

4. A heat and vibration sensitive switch, comprising a non-conductingbase, a pendulum support connected to said base, a pendulum rod at leastpart of which has a high coefiicient of expansion carried by saidsupport, a second support connected to said base, at least onethemoscopic rod connected to said second support and adjacent saidpendulum rod, and a bolt carried by said pendulum rod extendingtransversely through the same and adjacent saidv thermoscopic rod. 5. Aheat and vibration sensitive switch, com--A prisihg a non-conductingbase, a pendulum support connected to said base, said support having aslot formed therein and two conical cavities spaced from said slot, apendulum rod extending through said slot, an inverted cradle member at yone end of said pendulum rod adapted to seatirr said conical cavities, aring slidable on said rod and below said support, said ring having athreaded aperture formed therein, a screw in said aperture forfriction-al engagement with said pendulum rod, a second supportconnected .to said base, at least one thermoscopic rod connected to saidsecond support and adjacent said pendu-f lum rod, and a bolt carried bysaid pendulum rod extending transversely through the same `and adjacentsaid thermoscopio rod.

6. A heat and vibration sensitive switch, comprising a non-conductingbase, a pendulum sup-- port connected t0 said base, a pendulum rod car.ried by said support, an eccentric rotatably mounted in said base andengaging said support for moving said support on saidbase, meansconnected to said eccentric for rotating the same, a second supportconnected to said base, at least one thermoscopic rod connected to saidsecond support and adjacent said pendulum rod, and a bolt carried bysaid pendulum rod extending transversely through the same and adjacentsaidI thermoscopic rod.

. WALTER P. T. HOLM.

j j i REFERENCES CITED The following references are of record inthe leof this patent: l. n

fJNITED STATES PATENTS Number l l kmaar/57 1,720,230

Name Date I Fassett May 18, 1915 Murray v July 9, 1929.

